Open AccessInfluence of Ammonium: Nitrate Ratio and Nitrogen Concentration on Nitrification Activity in Soilless Potting Media
Author(s) -
Harvey J. Lang,
George C. Elliott
Publication year - 1991
Publication title -
journal of the american society for horticultural science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.408
H-Index - 80
eISSN - 2327-9788
pISSN - 0003-1062
DOI - 10.21273/jashs.116.4.642
Subject(s) - potting , ammonium , chemistry , nitrification , nitrogen , fertilizer , oxidizing agent , human fertilization , nitrate , horticulture , ammonium nitrate , zoology , botany , agronomy , biology , materials science , organic chemistry , composite material
Effects of medium, NH 4 : N0 3 , ratio, and N fertilizer rate on the development of NH 4 oxidation in soilless potting media were evaluated. In two separate experiments, NH 4 oxidizing activity increased to a maximum (4 to 6 weeks of cropping) and then dropped off sharply. Ammonium oxidation activity varied significantly among types of soilless potting media. Media fertilized with 1 NH 4 -N: 3 N0 3 -N had higher rates of NH 4 oxidation than media fertilized with ratios of either 1:1 or 3:1. Nitrogen fertilization at 15 m m gave consistently higher oxidation rates than fertilization at 30 m m . In general, media samples that had been cropped with plants had higher nitrifying activity than unplanted samples. Ammonium oxidation rate over all observations was significantly correlated with medium pH ( r = 0.50). pH values above 6.8 were necessary but not completely sufficient for relatively high rates of NH 4 oxidation. Rates of oxidation were insignificant with pH values <5.6.